Unirest, formerly associated with Mashape (now known as Kong Inc.), is an HTTP library designed to simplify the process of sending HTTP requests. It provides a straightforward API for performing RESTful operations across multiple programming languages, supporting asynchronous and synchronous requests. Unirest is particularly useful for developers seeking an easy-to-use tool for integrating third-party APIs with their applications. The library handles essential functions like managing connections, handling responses, and supporting various content types.